Stamp-mill tappet.



M; P. BOSS. I STAMP MILL TAPPET.

APPLIGATION FILED JAN.12,1905.

901,417. Patented Oct. 20, 1908.

F g- '0 v] I 1 Maww UNITED STATES PATENT OFFICE.

MARTIN P. BOSS, OF SAN FRANCISCO, CALIFORNIA.

STAMP-MILL TAPPET.

Application filed January 12, 1905.

To all whom it may concern:

Be it known that I, MARTIN P. Boss, a citizen of the United States, residing in the city and county of San Francisco, State of California, have invented certain new and useful Improvements in Stamp-Mill Tappets; and I do hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to the class of tappets for stamp-stems of stamp-mills.

The strains to which tappets are subjected, due to the blows of the cams, and which result in disalining tendencies and influences, causing the tappet eventually to work upward on the stem, have long since led to the suggestion and en'iployment of a counter-bore in the tappet opposite the gib which receives the pressure of the key. This counterbore is, in practice, made by machine work after the tappet is otherwise finished, and consists of a depression in one side of the main bore, struck from a center eccentric to that of said bore, said counterbore having a width greater or less as the case may be, the idea being to thus provide parallel lines for the stem contact opposite the gib, which will require less key 0 pressure. Notwithstanding this decided advantage of the countcrbore, once fully appreciated, it is less generally used today than formerly, because manufacturers can save a little expense when it is not exacted.

The object of my invention may be said to be two fold, namely, to provide a tappet having, first, a channel or depression the equivalent of and enjoying the advantages of a counterbore, without entailing the expense thereof in manufacture; and having, second, such channel or depression of particular and advantageous form. These objects are attained by casting in the tappet, a channel concentric with the stem bore and joining it at each side with the bore by straight walls, which give at their angles with said stem bore the necessary parallel lines of contact with the stem the channel having a width sufficient to separate said lines of contact with the stem by a proper distance, to enable the latter to act as a wedge between them Specification of Letters Patent.

Patented Oct. 20, 1908.

Serial No. 240,717.

under the minimum key pressure against the gib, thus doing away with that heavy driving of keys, which involves time and wear and tear.

Referring to the accompanying drawings for a more complete explanation of my invention Figure 1 is a longitudinal section of my improved tappet. Fig. 2 is a cross section of the same on the line 00-00 of Fig. 1.

The tappet A is of the general or usual form, having the stem-bore a, the gib B at one side of said bore, and the taper keys C. The tappet, instead of having the usual eccentric machine-m ade counterbore, is cast with a channel a opposite the gib, which channel in its best form is concentric with the stem bore, and oins the latter by straight side walls a which give along their angles at c the necessary parallel lines of contact with the stem, which latter under less heavy pressure of the keys against the gib is enabled to act as a wedge between said lines, for the reason that said lines are separated by a distance to give a practical wedging angle. The channel a being concentric with the stem-bore enables me to increase the diameter of the latter at its end (as seen at a in Fig. 1, and as shown bythe dotted line in Fig. 2) symmetrically with said channel, that is on the same radius, thereby providing for the uniform wear of the end of the tappet, which end thus presents a uniform annular face to the full width of the face of the cam. The cam must necessarily have a clearance space between itself and the stem, and if the tappet end should fit close up to the stem, the wear would result in a wasting away of the tappet end, leaving behind that portion close to the stem which is cleared by the cam. But by enlarging the stem-bore atthe end on a radius the same as that of the channel, the end presents an annulus of uniform width, equal to that of the cam, and will wear evenly.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is- A stamp mill tappet having a stem bore,

wall of the bore at points of the separation approximately but slightly less than the length of the diameter of the bore, whereby the stem may be wedged between said end walls the wedging points on the stem being separated approximately but slightly less than the length of the diameter thereof.

In witness whereof I have hereunto set my hand.

MARTIN P. BOSS.

lVitnesses J. COMPTON, D. B. RICHARDS. 

